Re: how to save the data of a JTable to a html file?

From:
Thomas Hawtin <usenet@tackline.plus.com>
Newsgroups:
comp.lang.java.programmer
Date:
Thu, 21 Sep 2006 17:49:02 +0100
Message-ID:
<4512c26f$0$557$ed2619ec@ptn-nntp-reader03.plus.net>
ant wrote:

how to save the data of a JTable to a html file?
now, I am doing a Java Applet program, and I need to save the content
of a JTable to html formatted file.
if you hava some useful suggestions or you know some third-party
components, please tell me!


Perhaps not directly relevant (it's a piece of cake to generate HTML
from the table model), but I thought I'd try using JTable itself (well,
the PL&F) to generate HTML. JTable supports copying as HTML via
clipboards and drag and drop, which we can exploit with a private
clipboard. Disappointing code and disappointing results below.

Some bad points:

  o You need to mutate the table (select all).
  o The APIs are cumbersome.
  o Actual requirements of the implementation are under specified.
  o The table is plain, with just toString applied to data.
  o Even the header isn't included.
  o There's no sensible extension mechanism.
  o It's not particularly efficiently coded.

Tom Hawtin

import java.awt.*;
import java.awt.datatransfer.*;
import javax.swing.*;

class ExportTableAsHTMLDemo {
     private static final DataFlavor HTML_STRING_FLAVOR;
     static {
         // The datatransfer API could do with some work here...
         try {
             HTML_STRING_FLAVOR = new DataFlavor(
                 "text/html;class=java.lang.String"
             );
         } catch (ClassNotFoundException exc) {
             // Don't even load class.
             throw new Error(exc);
         }
     }
     public static void main(String[] args) {
         java.awt.EventQueue.invokeLater(new Runnable() {
                 public void run() {
                     go();
                 }
         });
     }
     public static void go() {
         // Some random data.
         javax.swing.JTable table = new javax.swing.JTable(
             new Object[][]{
                 new Object[] { "some", "data" },
                 new Object[] { "more", "data" },
             },
             new Object[] { "Col A", "Col B" }
         );

         // Exports selected data only.
         table.selectAll(); // Evil.

         javax.swing.TransferHandler handler =
             table.getTransferHandler();
         if (handler == null) {
             System.err.println("No transfer handler.");
             return;
         }
         int actions = handler.getSourceActions(table);
         if ((actions & javax.swing.TransferHandler.COPY) == 0) {
             System.err.println("Table does not support copy.");
             return;
         }

         java.awt.datatransfer.Clipboard clipboard =
             new java.awt.datatransfer.Clipboard(
                 "Export table as HTML private clipboard"
             );
         try {
             handler.exportToClipboard(
                 table, clipboard, javax.swing.TransferHandler.COPY
             );
         } catch (IllegalStateException exc) {
             exc.printStackTrace();
             return;
         }
         java.awt.datatransfer.Transferable transferable =
             clipboard.getContents(/* unused... */null);
         if (transferable == null) {
             System.err.println("Clipboard empty");
             return;
         }
         // Just support HTML as String.
         // Could also use HTML as Reader or UTF-8 InputStream
         // (particularly for large tables,
         // if the implementation was better).
         if (!transferable.isDataFlavorSupported(HTML_STRING_FLAVOR)) {
             System.err.println("HTML (String) not supported");
             return;
         }
         try {
             Object data = transferable.getTransferData(
                 HTML_STRING_FLAVOR
             );
             System.out.println(data);
         } catch (java.io.IOException exc) {
             exc.printStackTrace();
             return;
         } catch (java.awt.datatransfer.UnsupportedFlavorException exc) {
             System.err.println("HTML (String) not supported");
             return;
         }
     }
}

<html>
<body>
<table>
<tr>
   <td>some</td>
   <td>data</td>
</tr>
<tr>
   <td>more</td>
   <td>data</td>
</tr>
</table>
</body>
</html>
--
Unemployed English Java programmer
http://jroller.com/page/tackline/

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